Biomedical subjects

W H Lo

Publications and source records attributed to W H Lo.

At least 19 recordsLinked to original sources

PubMed2006

Acute renal failure associated with prolonged intake of slimming pills containing anthraquinones.

Chinese herbal medicine preparations are widely available and often regarded by the public as natural and safe remedies for a variety of medical conditions. Nephropathy caused by Chinese herbs has previously been reported, usually involving the use of aristolochic acids. We report a 23-year-old woman who developed acute renal failure following prolonged use of a proprietary Chinese herbal slimming pill that contained anthraquinone derivatives, extracted from Rhizoma Rhei (rhubarb). The renal injury was probably aggravated by the concomitant intake of a non-steroidal anti-inflammatory drug, diclofenac. Renal pathology was that of hypocellular interstitial fibrosis. Spontaneous renal recovery occurred upon cessation of the slimming pills, but mild interstitial fibrosis and tubular atrophy was still evident histologically 4 months later. Although a causal relationship between the use of an anthraquinone-containing herbal agent and renal injury remains to be proven, phytotherapy-associated interstitial nephropathy should be considered in patients who present with unexplained renal failure.

Acute Kidney Injury↗

PubMed2005

Effects of fatty acids on growth and poly-3-hydroxybutyrate production in bacteria.

The effects of saturated and unsaturated fatty acids (lauric acid, palmitic acid, steric acid, oleic acid, linoleic acid, soybean oil) on Sphaerotilus natans, 0B17 (Pseudomonas sp.), and recombinant Escherichia coli DH5(/pUC19/CAB were studied. Oleic acid enhances Poly-3-hydroxybutyrate (PHB) production in these three bacterial strains, suggesting that the single double bond of the acid activates the polyhydroxylkanoate accumulation enzymatic reaction. Under the effect of lauric acid and linoleic acid, the growth of S. natans and 0B17 were totally inhibited. However, the enhanced PHB accumulation in recombinant E. coli was observed.

Bioreactors↗

PubMed2005

Microbial synthesis and characterization of physiochemical properties of polyhydroxyalkanoates (PHAs) produced by bacteria isolated from activated sludge obtained from the municipal wastewater works in Hong Kong.

The first objective of this study was the measurement of physical properties of P(3HB-co-3HV) copolymers with different (hydroxybutyrate) HB to (hydroxyvalerate) HV ratios produced by Bacillus cereus (TRY2) isolated from activated sludge. The 3HV PHBV copolymers were 0.05, 22.6, 39.2, 54.1, and 69.1 mol%, respectively. The second objective was to study possible waste water treatment and production of PHAs at the same time by B. cereus (TRY2) and Pseudomonas spp. (TOB17) (both were isolated from activated sludge), recombinant Bacillus DH5alpha, and a combination of the above three bacteria. The results were satisfactory; the maximum COD and TOC of the sewage sludge reduced were 53.5% and 67.5%, respectively.

Bacillus cereus↗

PubMed2004

Remission of hepatocellular carcinoma with arginine depletion induced by systemic release of endogenous hepatic arginase due to transhepatic arterial embolisation, augmented by high-dose insulin: arginase as a potential drug candidate for hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is auxotrophic for the semi-essential amino acid arginine, depletion of which leads to tumor death. In humans, arginine is not an essential amino acid since many adult somatic cells can re-synthesize it from other sources, such as citrulline. Enzymes capable of depleting arginine in vitro include the urea cycle enzyme arginase, which is found in abundance in human liver. For over three decades, arginase has not been considered as a potential drug candidate because of its low substrate affinity, short circulatory half-life and sub-optimal enzymatic activity at physiological pH, though its in vitro anti-tumor activities in certain tumors have been amply reported. Arginine deiminase, a bacterial enzyme from Mycoplasma hominus has been shown to induce HCC remission through the mechanism of arginine depletion. We report here an innovative treatment approach for the treatment of locally advanced and metastatic HCC with transhepatic arterial embolisation (TAE) of the liver tumor with lipiodol and gel foam as a means of inducing a leakage of hepatic arginase from the liver into the circulation. Hepatic arginase released into the systemic circulation rapidly depleted plasma arginine. High-dose insulin was included to induce a state of hypoaminoacidaemia to augment arginine depletion. With this protocol, we have treated seven patients with locally advanced and/or metastatic HCC. Five patients achieved arginine depletion, ranging from 0 to 20 microM (normal plasma level 100-120 microM); all had varying degrees of tumor remission in their primary tumors and extra-hepatic sites in the lymph nodes, lungs and bones, suggesting systemic anti-cancer effect of arginine depletion. The two non-responders did not show significant reduction in plasma arginine. Based on our findings, we propose that the urea cycle enzyme, arginase, is a good drug candidate for the treatment of HCC.

Adult↗

PubMed2003

Ni2+ removal and recovery from electroplating effluent by Pseudomonas putida 5-x cell biomass.

Ni2+ and Cu2+ are the major heavy metal ions in electroplating wastewater of Hong Kong. In the present study, Pseudomonas putida 5-x cell biomass was used to remove Ni2+ from electroplating effluent. Ni2+ adsorption capacity of P. putida 5-x cell biomass cultured in sulphate-limiting medium was found to be minimum in early logarithmic growth phase, and maximum of 28.1 mg g(-1) in late stationary growth phase. Pretreated cells by 0.1 mol L(-1) HCl could greatly enhance the Ni2+ adsorption capacity of cell biomass from 28.1 to 36.7 mg g(-1) and had no significant effect on biomass loss. The adsorption process of P. putida 5-x fresh cells and pretreated cell all could be expressed with Freundlich isotherm. TEM analyses indicated that acidic pretreatment degraded the superficial layer-capsule outside of the fresh cell to improve the adsorption capacity of cell to Ni2+. The Ni2+ bound by P. putida 5-x cell biomass could be efficiently recovered using 0.1 mol L(-1) HCl, and the cell biomass could be reused at least five cycles for Ni2+ removal and recovery with 93% above removal efficiency and 98% above recovery rate. Owing to the Cu2+ presented in electroplating wastewater inhibiting Ni2+ adsorption process by P. putida 5-x cell biomass, two-stage biosorption processes should be designed to remove and recover Cu2+ and Ni2+ sequentially from electroplating effluent.

Adsorption↗

PubMed2003

Thrombotic thrombocytopenic purpura as a rare complication in childhood systemic lupus erythematosus: case report and literature review.

Thrombotic thrombocytopenic purpura is a rare but serious condition in childhood. It can be idiopathic or a complication of other diseases or drug therapy. We report on a 12-year-old Chinese girl who presented with fulminant systemic lupus erythematosus with progressive renal failure, pancytopenia, and cerebral dysfunction due to thrombotic thrombocytopenic purpura. The patient also had Pneumocystis carinii pneumonia, Pseudomonas septicaemia, and Herpes zoster infections as a result of immunosuppressive treatment. She responded to combined therapy with pulse methylprednisolone, cyclophosphamide, plasmapheresis, and intensive care support, and completely recovered renal and neurological function. A review of the English-language medical literature since 1968 identified 20 other paediatric cases of systemic lupus erythematosus and thrombotic thrombocytopenic purpura. Clinical features, treatment, and outcome of these cases are presented and discussed. Early recognition is important, and although plasmapheresis is not of proven benefit in severe cases of systemic lupus erythematosus, it is life-saving in lupus-related thrombotic thrombocytopenic purpura and must be instituted early to avoid a poor outcome.

Child↗

PubMed2002

Treatment of malignant bone tumours by extracorporeally irradiated autograft-prosthetic composite arthroplasty.

Autogenous bone graft which has been either autoclaved or irradiated is commonly used in oriental countries as an alternative to allograft. We started to use the technique of extracorporeal irradiation of the resected specimen and reimplantation (ECIR) in 1991. There was, however, a high incidence of fracture of the irradiated bone and loss of articular cartilage. In an attempt to reduce these complications, we combined the irradiated autograft with a conventional arthroplasty. Between 1995 and 1998, 14 patients underwent limb salvage by this method. Seven had an osteosarcoma, two bony metastases, three a chondrosarcoma, one a malignant fibrous histiocytoma, and one a leiomyosarcoma. Ten tumours were located in the proximal femur, two in the proximal humerus, and two in the distal femur. One patient who had a solitary metastasis in the proximal part of the left femur died from lung metastases 13 months after operation. The remaining 13 patients were alive and without evidence of local recurrence or distant metastases at a mean follow-up of 43 months (28 to 72). Postoperative palsy of the sciatic nerve occurred in one patient, but no complications such as wound infection, fracture, or nonunion were seen. All host-irradiated bone junctions healed uneventfully within eight months. Using the Enneking functional evaluation system, the mean postoperative score for all 14 patients was 80% (57 to 93). The use of irradiated autograft prosthesis composites reduces the complications of ECIR and gives good functional results. It may be a good alternative in limb-salvage surgery, especially in countries where it is difficult to obtain allografts.

Adolescent↗

PubMed2001

Intertrochanteric fractures in adults younger than 40 years of age.

This study reviewed 66 intertrochanteric fractures in patients younger than 40 years old (average 33.0 years old; range 17-40 years old). In contrast to the usual population with intertrochanteric fractures, the factors male predominance (46/66), less pre-injury comorbidity (9/66), more outdoor high energy trauma (47/66), and more associated injuries (32/66) were evident. The distribution of associated injuries was wide. Some of them were life threatening. According to Boyd's classification, 20 were type I, 24 were type II, 13 were type III, and 9 were type IV. Twenty-nine were stable, and 37 were unstable. Stratified by the mechanism of injury, the difference in distribution between the subgroups was significant (p = 0.027, two-tail Fisher's exact test). Simple falls only caused Boyd type I and II fractures. Boyd type III or IV fractures were found more often after vehicular trauma or falls from a height. All the intertrochanteric fractures healed on average 70.5 days (range 31-213 days) after operation. The fractures resulting from vehicular trauma or fall from a height healed significantly more slowly (p = 0.02, univariant log-rank test). There were 6 intertrochanteric fracture-related complications. The mechanism of injury determines the character of intertrochanteric fractures in young adults. Given tougher bone stock, better healing ability, and less co-morbidity, proper management can lead to healing of all intertrochanteric fractures. The extent of functional recovery was also determined by the associated injuries.

Adolescent↗

PubMed2001

Avascular necrosis of femoral head after gamma-nailing for unstable intertrochanteric fractures.

We reported on 7 cases of avascular necrosis of the femoral head after treatment of an unstable intertrochanteric fracture with the Asian Pacific gamma-nail. The incidence was about 1.16% (7 of 604) in our series. Good reduction and good implant position were achieved in all 7 men. Avascular necrosis was found about 6 months to 3 years after the initial operation, and all the fractures were solidly united at the final diagnosis. The possible etiologies were initial high energy trauma and combining basal neck fracture and iatrogenic damage of the blood supply to the femoral head.

Adult↗

PubMed2001

Cerclage wiring in displaced both-column fractures of the acetabulum.

We evaluated the effect of cerclage wiring in the open reduction and internal fixation of displaced both-column fractures of the acetabulum. This was a prospective clinical evaluation of such cases where the main surgical strategy was open reduction and internal fixation with cerclage wire and supplemental reconstruction plates. Data on 35 cases treated by open reduction (all via the triradiate approach)/internal fixations with cerclage wire and reconstruction plates were collected. The follow-up period was 40 months (18-69). Reduction with a fracture gap of less than 2 mm without articular stepping was achieved in all 35 cases. Postoperative complications developed in seven cases, including subcutaneous haematoma in two, wound infection in two and heterotopic ossification in three. All the complications had no adverse effect on the clinical outcome, and all the cases had good to excellent final results. Cerclage wiring is very useful and effective in the reduction and fixation of displaced both-column fractures of the acetabulum, and supplemental fixation with reconstruction plates and screws is necessary.

Acetabulum↗

PubMed2001

The influence of inserting a Fuji pressure sensitive film between the tibiofemoral joint of knee prosthesis on actual contact characteristics.

OBJECTIVE: To investigate the influence of inserting a Fuji pressure sensitive film between the tibiofemoral joint of knee prosthesis on actual contact characteristics. DESIGN: A finite element analysis was used to investigate the alteration of contact characteristics of the tibiofemoral joint due to inserting a pressure sensitive film between the contacting surfaces. BACKGROUND: The discrepancy between actual contact behaviors of tibiofemoral joint of knee prosthesis and the measurement using Fuji pressure sensitive film was not discussed extensively. The change of direct contact circumstance of the tibiofemoral joint due to inserting a pressure sensitive film was not well reported. METHOD: A two-dimensional finite element model of the tibiofemoral joint of knee prosthesis in the sagittal plane was constructed. Four different radii of the femoral component were used to investigate the conformity effect. Two-layers of plane strain element were used to model the pressure sensitive film. The influence of inserting a pressure sensitive film on the actual contact characteristics was analyzed by comparing the results of the change in contact radius. RESULTS: Inserting a pressure sensitive film between contacting surfaces would disturb the original contact behaviors, especially in the lowest conformity design. The maximum difference of contact radius between the model simulating actual contact circumstance and the model with inserting a pressure sensitive film between contacting surface was 77% in the lowest conformity condition at the smallest load. CONCLUSIONS: This study proposes a quantitative analysis of contact characteristics in the tibiofemoral joint of knee prosthesis between the models with and without inserting a pressure sensitive film into the contact surface. The measurement of contact area in artificial tibiofemoral joints by using Fuji pressure sensitive film is always overestimated its true contact area by 14-77%. RELEVANCE: This study revealed the measurement of contact characteristics of artificial tibiofemoral joints by using Fuji pressure sensitive film which depends on not only the applied load, but also the conformity and material properties of the contact surface. Therefore, the information of the conformity and material properties of the contact surface should be provided as well as the applied load wherever a measurement of contact characteristics using Fuji pressure sensitive film is analyzed and interpreted.

Biomechanical Phenomena↗

PubMed2001

Stress analysis of the disc adjacent to interbody fusion in lumbar spine.

After anterior interbody fusion in the lumbar spine, the accelerated degeneration of the disc adjacent to the fusion levels was clinically observed. To understand the stress distribution of the adjacent disc, this study created a finite element model of the lumbar spine from L1-L5 vertebral body. The fusion model modified from the intact model was used to simulate the anterior interbody fusion. Various loading conditions, which included flexion, extension, lateral bending, and torsion, were applied to the finite element model to study the corresponding stress distribution. From the finite element model calculation, at a lower fusion site or more fusion levels, the stress of the disc adjacent to interbody fusion increased more than upper fusion site or single fusion level under flexion, torsion and lateral bending. Larger stress increase was estimated at the upper disc adjacent to interbody fusion than the lower disc adjacent to interbody fusion. In stress distribution, the upper disc adjacent to interbody fusion had a little alteration under torsion.

Finite Element Analysis↗

PubMed2001

DSPP mutation in dentinogenesis imperfecta Shields type II.

We identified a nonsense mutation (Gln45stop) in exon 3 of the dentin sialophosphoprotein (DSPP) gene in a Chinese family with dentinogenesis imperfecta Shields type II (DGI-II), in which the affected members showed discoloration and severe attrition of their teeth, with obliterated pulp chambers.

Asian People↗

PubMed2001

Cefuroxime-impregnated cement at primary total knee arthroplasty in diabetes mellitus. A prospective, randomised study.

We have performed a prospective single-blinded randomised study to evaluate the role of antibiotic-impregnated cement in the prevention of deep infection at primary total knee arthroplasty (TKA) in patients with diabetes mellitus. We studied prospectively 78 arthroplasties performed for osteoarthritis in such patients. They were randomly separated into two groups. In group 1 (41 knees), cefuroxime-impregnated cement was used while in group 2 (37 knees) cefuroxime was not added to the cement. The preoperative, intraoperative and postoperative management was the same for both groups. The mean follow-up was 50 months (26 to 88). There were no cases of deep infection in group 1, but five (13.5%) occurred in group 2 (p = 0.021). We conclude that cefuroxime-impregnated cement is effective in the prevention of deep infection at primary TKA in patients with diabetes mellitus.

Aged↗

PubMed2000

Treatment of acute closed humeral shaft fractures with Ender nails.

The effect of semirigid Ender nails (EN) in the treatment of closed humeral shaft fractures was reviewed and analyzed. Clinical study was set retrospectively with detailed parameters. One hundred and eighteen closed humeral shaft fractures, treated with closed reduction and internal fixation with ENs, were collected. The follow-up period was 78 (24-175) months. The average operation blood loss was 105 cc, operation time was 57 min, hospital stay was 6.5 days, and union time was 10.5 weeks. The postoperative complications included three superficial infections, one iatrogenic radial nerve palsy, eight nail backouts, and eight nonunions. In our experience, for closed humeral shaft fractures fixed surgically, EN is a good choice for its simplicity and efficacy, but the fracture gap should be minimized after fixation and postoperative care should be closely observed.

Adolescent↗

PubMed2000

Ipsilateral hip and distal femoral fractures.

We tried to find the trauma mechanism and treatment rationale of ipsilateral concomitant hip and distal femoral fractures involving the articular surface. Between 1988 and 1995, 15 cases of ipsilateral hip (confined to neck or trochanteric areas of the femur) and distal (confined to supra- and intercondylar area of the femur) femoral articular fractures were collected. The hip fractures consisted of 10 trochanteric fractures and five neck fractures, which were managed with reduction and fixation in 14 (Knowles' pin in eight, DHS in four and standard Gamma nail in two), and primary bipolar hemiarthroplastry in one. The distal femoral articular fractures were open in 11; these were managed with radical debridement, implantation of Septopal chains and immediate internal fixation, followed by prophylactic autogenous bone grafting 6 weeks later in the recent six cases (five Judet plates, four dynamic condylar screws and two condylar plates). The other four closed distal femoral fractures were managed with early reduction and internal fixation (two Judet plate, one dynamic condylar screw and one condylar plate). The union time was 20.3 (12-48) weeks for proximal fractures and 23.7 (12-36) weeks for distal fractures. Early infection developed in three cases. Nonunion of a femoral neck fracture developed in one case. The other complications were implant failure in one, coxa vara in one, refracture in one, delayed union in one and knee stiffness in one.

Adult↗

PubMed2000

Surgical treatment of displaced acetabular fractures - 72 cases followed for 10 (6-14) years.

Seventy-two displaced acetabular fractures managed surgically were evaluated retrospectively. The follow-up period was 10 (6-14) yr. The commonest fractures were posterior wall (28) and both columns (10). The surgical approaches were Kocher-Langenbeck (47), ilioinguinal (19) and extended iliofemoral (6). No neural monitoring was used in operations and no preventive agents for heterotopic ossification or thromboembolism were used perioperatively. Reduction was rated congruent in 59 (81.9%) and noncongruent in 13 (18.1%). The early postoperative complications were 1 vascular injury, 1 iatrogenic sciatic nerve injury, 1 deep vein thrombosis and 2 wound infections. The late complications were heterotopic ossification in 20 patients, avascular necrosis of the femoral head in 4 and symptomatic arthritis in 10. Functional outcomes were rated as excellent in 31, good in 23, fair in 7 and poor in 11. Our results show that traditional management is effective enough for displaced acetabular fractures.

Acetabulum↗

PubMed2000

The effect of posterior capsulorrhaphy in primary total hip arthroplasty: a prospective randomized study.

Between 1994 and 1997, 180 cases of primary total hip arthroplasty (THA) were performed with the posterior (Moore) approach for a variety of indications and studies prospectively. The cases were separated randomly into 2 groups to evaluate the effect of posterior capsulorrhaphy in the prevention of postoperative dislocation. In group 1 (96 cases), closure of the arthroplasty was performed with a posterior capsulorrhaphy; in group 2 (84 cases), closure was performed without capsulorrhaphy. The follow-up period was 38 months (range, 12-60 months). No dislocations occurred in group 1, whereas 2 dislocations (2.3%) occurred in group 2. Although the factors affecting dislocation in primary THA are many, a posterior capsulorrhaphy may be helpful in the prevention of posterior dislocation of primary THA performed with a posterior approach.

Arthroplasty, Replacement, Hip↗